feat(auth): implement user authentication with JWT and NextAuth

- Added user registration and login functionality with JWT authentication.
- Created auth controller, service, and module in the backend.
- Implemented user model and user products management.
- Integrated NextAuth for session management on the frontend.
- Added middleware for protecting routes and handling public access.
- Updated frontend API routes to include authorization headers.
- Enhanced recipe and user product models to support ownership and visibility.
- Created registration and login pages in the frontend.
- Added necessary types for NextAuth session management.

backend/src/recipes/recipes.service.ts

@@ -290,27 +290,45 @@ export class RecipesService {
     };
   }
 
-  async findAll() {
+  async findAll(userId: number) {
     return this.prisma.recipe.findMany({
+      where: {
+        OR: [
+          { isPublic: true },
+          { ownerId: userId },
+          { shares: { some: { userId } } },
+        ],
+      },
       include: {
         ingredients: {
           include: {
             product: { include: { nutrition: true } },
           },
         },
+        owner: { select: { id: true, username: true } },
+        shares: { select: { userId: true } },
       },
     });
   }
 
-  async findOne(id: number) {
-    const recipe = await this.prisma.recipe.findUnique({
-      where: { id },
+  async findOne(id: number, userId: number) {
+    const recipe = await this.prisma.recipe.findFirst({
+      where: {
+        id,
+        OR: [
+          { isPublic: true },
+          { ownerId: userId },
+          { shares: { some: { userId } } },
+        ],
+      },
       include: {
         ingredients: {
           include: {
             product: { include: { nutrition: true } },
           },
         },
+        owner: { select: { id: true, username: true } },
+        shares: { select: { userId: true } },
       },
     });
 
@@ -321,8 +339,8 @@ export class RecipesService {
     return recipe;
   }
 
-  async update(id: number, updateRecipeDto: CreateRecipeDto) {
-    // Verifiera att receptet finns
+  async update(id: number, updateRecipeDto: CreateRecipeDto, userId: number) {
+    // Verifiera att receptet finns och att användaren äger det
     const existingRecipe = await this.prisma.recipe.findUnique({
       where: { id },
     });
@@ -331,6 +349,11 @@ export class RecipesService {
       throw new NotFoundException(`Recipe with id ${id} not found`);
     }
 
+    // Tillåt uppdatering om användaren är ägare ELLER om receptet är publikt utan ägare
+    if (existingRecipe.ownerId !== null && existingRecipe.ownerId !== userId) {
+      throw new NotFoundException(`Recipe with id ${id} not found`);
+    }
+
     // Ta bort gamla ingredienser
     await this.prisma.recipeIngredient.deleteMany({
       where: { recipeId: id },
@@ -344,6 +367,7 @@ export class RecipesService {
         description: updateRecipeDto.description || null,
         instructions: updateRecipeDto.instructions || null,
         servings: updateRecipeDto.servings ?? null,
+        ...(updateRecipeDto.isPublic !== undefined && { isPublic: updateRecipeDto.isPublic }),
         ...(updateRecipeDto.imageUrl !== undefined && { imageUrl: updateRecipeDto.imageUrl || null }),
         ingredients: {
           create: updateRecipeDto.ingredients.map((ingredient) => ({
@@ -366,7 +390,7 @@ export class RecipesService {
     return recipe;
   }
 
-  async remove(id: number) {
+  async remove(id: number, userId: number) {
     const existingRecipe = await this.prisma.recipe.findUnique({
       where: { id },
     });
@@ -375,6 +399,10 @@ export class RecipesService {
       throw new NotFoundException(`Recipe with id ${id} not found`);
     }
 
+    if (existingRecipe.ownerId !== null && existingRecipe.ownerId !== userId) {
+      throw new NotFoundException(`Recipe with id ${id} not found`);
+    }
+
     await this.prisma.recipeIngredient.deleteMany({ where: { recipeId: id } });
     await this.prisma.recipe.delete({ where: { id } });
   }
@@ -394,7 +422,7 @@ export class RecipesService {
     });
   }
 
-  async create(createRecipeDto: CreateRecipeDto) {
+  async create(createRecipeDto: CreateRecipeDto, userId: number) {
     // Om imageUrl är en extern URL — ladda ner och optimera
     let imageUrl: string | null = createRecipeDto.imageUrl || null;
     if (imageUrl && imageUrl.startsWith('http')) {
@@ -413,6 +441,8 @@ export class RecipesService {
         instructions: createRecipeDto.instructions || null,
         imageUrl,
         servings: createRecipeDto.servings ?? null,
+        ownerId: userId,
+        isPublic: false,
         ingredients: {
           create: createRecipeDto.ingredients.map((ingredient) => ({
             productId: ingredient.productId,